How effective is the flu vaccine, and will getting vaccinated reduce the severity of your illness even if the vaccine is a poor match to circulating influenza virus strains? While public health officials insist vaccination is the best way to prevent the seasonal flu, the evidence calls this assumption into question, and most health care professionals won’t even get the flu shot if it’s voluntary.1

In its 2014 meta-analysis2 of the available research on inactivated influenza vaccines, the Cochrane Collaboration (which is considered by many as the gold-standard for scientific meta-reviews), reviewed evidence related to influenza and influenza-like illness (ILI) that people experience during flu seasons and stated:

“Over 200 viruses cause ILI, which produces the same symptoms (fever, headache, aches, pains, cough and runny nose) as influenza. Without laboratory tests, doctors cannot distinguish between ILI and influenza because both last for days and rarely cause serious illness or death.

The types of virus contained in influenza vaccines are usually those that are expected to circulate in the following influenza seasons, according to recommendations of the World Health Organization (seasonal vaccine).”

The Cochrane researchers concluded that:

“Injected influenza vaccines probably have a small protective effect against influenza and ILI (moderate-certainty evidence), as 71 people would need to be vaccinated to avoid one influenza case, and 29 would need to be vaccinated to avoid one case of ILI. Vaccination may have little or no appreciable effect on hospitalizations (low-certainty evidence) or number of working days lost.”

If 71 people have to be vaccinated in order for a single case of influenza to be avoided, this means that flu shots have a rather abysmal effectiveness rating. And it isn’t surprising that flu shots have “little or no appreciable effect on hospitalizations or number of working days lost,” considering its ineffectiveness at preventing illness. Similarly, while many assert that getting vaccinated will render flu symptoms less severe — should it fail to protect you after all — there’s really no good evidence for this either.

Interim Estimates of Flu Vaccine Effectiveness Are In

On February 16, the CDC published interim estimates of the 2017/2018 seasonal influenza vaccine’s effectiveness for the U.S.3 Based on data from 4,562 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network between November 2, 2017 and February 3, 2018, the CDC reports the overall adjusted vaccine effectiveness against “influenza A and influenza B virus infection associated with medically attended acute respiratory illness” was 36 percent. More precisely, vaccine effectiveness is estimated to be:

25 percent effective against the A(H3N2) virus

67 percent effective against A(H1N1)pdm09 viruses

42 percent effective against influenza B viruses

In 2015, a CDC analysis4 revealed that, between 2005 and 2015, the flu vaccine was less than 50 percent effective more than half of the time, so this year’s low effectiveness rating (36 percent) comes as no great surprise. However, there’s a significant problem with how this effectiveness rating is attained. As in previous years, the 4,562 individuals upon which this statistic is derived were all diagnosed with an acute respiratory illness. No healthy people were included.

To be eligible for inclusion, they had to have developed an acute respiratory infection with cough at least seven days prior to admittance. They also could not have been treated with antiviral medication. Participants were interviewed about their health status, symptoms, and flu vaccination status.

Swabs were taken to identify the virus responsible for the infection. In all, 38 percent of subjects tested positive for influenza virus (the rest had respiratory symptoms that looked like influenza but were actually caused by other types of viruses or bacteria).

The percentage of patients who were vaccinated ranged between 45 and 59 percent, depending on which of the five study sites they belonged to. Of those who tested positive for influenza, 43 percent had received the 2017/2018 seasonal flu vaccine. Of those whose illness was related to another type of viral or bacterial organism, 53 percent had been vaccinated against seasonal influenza.

Ironically, CDC officials continue to “recommend influenza vaccination because the vaccine can still prevent some infections with currently circulating influenza viruses,”5 completely ignoring that simple vitamin D supplementation has greater efficacy and none of the risks associated with flu shots.

If preventing “some” infections is good enough for vaccines, why isn’t preventing more of them with vitamin D a viable alternative? I’ll discuss this further toward the end of this article, as research clearly demonstrates the effectiveness of vitamin D when it comes to prevention of illness during the flu season.

Does Vaccination Really Lessen Flu Symptoms?

While health officials are fond of saying that getting a flu shot will lessen your symptoms should you contract influenza, French researchers disagree, noting that “very few studies have addressed the question of whether the vaccine mitigates influenza severity among those who develop the illness despite being vaccinated.”

Vaccine researchers in France decided to test the hypothesis by looking at data from vaccinated and unvaccinated elderly patients diagnosed with influenza. The results were published in April 2017.6 What they found was a rather insignificant lessening of symptoms, limited to a reduction in initial headache complaints among those who had been vaccinated:

“Compared to non-vaccinated influenza patients, those who had been vaccinated had a slightly reduced maximum temperature and presented less frequently with myalgia, shivering and headache. In stratified analyses, the observed effect was limited to patients infected with A(H3) or type B viruses. After adjusting by age group, virus (sub)type and season, the difference remained statistically significant only for headache, which was less frequent among vaccinated individuals.”

How and Why the Flu Shot Might Make You More Susceptible to the Flu

Not only is substantial scientific evidence for symptom alleviation lacking, there’s reason to suspect influenza vaccine may actually have the ability to make you more vulnerable to infection, and there are plenty of anecdotal reports that for some people it can be more severe than infection acquired from exposure to influenza viruses in the environment.

In a September 2017 Medium article,7 Andre Angelantoni counters claims made by Carol Lynn Curchoe, Ph.D., who in an earlier article8 stated that “Getting the flu shot ‘primes’ your body to recognize and fight all strains of the flu.” This, apparently, has become a commonly accepted myth, even among some health professionals but, as explained by Angelantoni, the vaccines don’t work that way:

“[Your] immune system is being programmed by the flu shot making it ready for the exact strains in the shot. It does not protect against other strains but instead opens you up to other flu strains and infection from other pathogens. It’s called heterologous immunity … an extension of basic immunology.

After all … Prevnar is superseded by Synflorix and Prevnar 13 because the body was not ‘primed’ to handle all strains of pneumococcus. It’s not clear where [Curchoe] got the idea that the flu vaccine has this magical ability that other vaccines do not and [she] provide[s] no reference for [her] assertion; it appears to be a completely made up ‘fact.’”

Heterologous Immunity and Directional Programming of Your Immune System

Angelantoni goes on to cite research I’ve covered on a number of occasions, such as the 2010 Canadian study9 that found people who were vaccinated against seasonal influenza were more susceptible to the pandemic H1N1 strain; the 2014 ferret study10 in which these effects were replicated; as well as a 2012 Chinese study11 that found a child’s chances of contracting a respiratory infection after getting the seasonal flu shot rose more than fourfold.

“Heterologous immunity roughly means ‘unequal immunity’ and it’s the concept that the immune system is programmed in a directional way,” Angelantoni writes. “This can sometimes work in the body’s favor if a subsequent antigen is similar enough to the one for which antibodies have just been made.

In this case, the directionality means that the body is already prepared to some degree because it has encountered a pathogen ‘similar enough’ to the new one. However, often it works against the body, too, as in the case of the flu vaccines. The body learns how to protect against the strains given in the shot and thereby — by design — becomes less able to handle other strains and other invaders.”

As noted in a 2014 paper on heterologous immunity:12

“Immunity to previously encountered viruses can alter responses to unrelated pathogens … Heterologous immunity … may be beneficial by boosting protective responses. However, heterologous reactivity can also result in severe immunopathology. The key features that define heterologous immune modulation include alterations in the CD4 and CD8 T cell compartments and changes in viral dynamics and disease progression.”

In other words, while influenza vaccine may offer some level of protection against the three or four viral strains included in the vaccine, depending on whether the vaccine used is trivalent or quadrivalent, it may simultaneously diminish your ability to ward off infection by other influenza strains and other types of viral or bacterial infections.

Heterologous immunity is also addressed in a 2013 paper,13 which notes that “vaccines modulate general resistance,” and “have nonspecific effects on the ability of the immune system to handle other pathogens.” It also states that:

“… [O]ur current perception of the immune system is … simplistic. It was, to a large extent, shaped in the 1950s with the formulation of the clonal selection hypothesis. This line of thinking has emphasized the adaptive immune system and the speciﬁc antigen recognition and speciﬁc memory, which have been crucial in vaccine development, perhaps at the expense of examining cross-reactive features of the immune system as well as the memory capacity of the innate immune system.

Although tens of thousands of studies assessing disease-speciﬁc, antibody-inducing effects of vaccines have been conducted, most people have not examined whether vaccines have nonspeciﬁc effects because current perception excludes such effects.”

Poor Immune Response Blamed for Low Flu Vaccine Effectiveness

Poor influenza vaccine effectiveness is often blamed on viral mutations occurring while the selected influenza viruses are grown in the lab but, according to a team of researchers from the University of Chicago and Harvard University, poor immune responses in individuals appear to be a more likely reason. In their study,14 the flu vaccine failed to elicit a strong immune response in most participants. As explained in the press release:15

“What’s at play seems to be a phenomenon known as ‘original antigenic sin.’ Flu vaccines are designed to get the immune system to produce antibodies that recognize the specific strains of the virus someone may encounter in a given year. These antibodies target unique sites on the virus, and latch onto them to disable it.

Once the immune system already has antibodies to target a given site on the virus, it preferentially reactivates the same immune cells the next time it encounters the virus. This is efficient for the immune system, but the problem is that the virus changes ever so slightly from year to year. The site the antibodies recognize could still be there, but it may no longer be the crucial one to neutralize the virus.

Antibodies produced from our first encounters with the flu, either from vaccines or infection, tend to take precedence over ones generated by later inoculations. So even when the vaccine is a good match for a given year, if someone has a history with the flu, the immune response to a new vaccine could be less protective.”

Philip Morris to Produce Next GMO Flu Vaccine Grown in Tobacco Plant

The fact that most flu vaccine viruses are grown in eggs, which allows the influenza virus to mutate ever so slightly, does contribute to mismatches between the vaccine and the most prevalent circulating influenza A and B strains in a given flu season, however. In a study published last year, egg adaptations were found to have caused mismatches in the most commonly used influenza vaccine during the 2016/2017 season. It may be a factor in this year’s low vaccine efficacy rating as well.

Some flu vaccine manufacturers are now starting to switch to vaccine strain viruses grown without eggs, using either genetically modified insect cells or canine kidney cells. The Canadian biotech company Medicago — owned by Philip Morris and Mitsubishi Tanabe Pharma — has also begun stage 3 clinical trials on a genetically engineered flu vaccine manufactured in Nicotiana benthamiana, a type of tobacco plant known for its ability to make proteins at a high rate of speed.16

Medicago is also using “virus-like particles” in lieu of inactivated influenza viruses. The particles have “the structure of the influenza virus but not its full genetic code.”

The company theorizes that these virus-like particles will “mobilize special immune cells to eliminate flu-infected cells, regardless of the subtype they may have mutated into.” This combination of factors allows Medicago to produce a vaccine in as little as six weeks, compared to the six months it normally takes to produce an egg-based vaccine.

As reported by Forbes,17 “The vaccine is produced by introducing genetic material from the flu virus into the plants, which are then incubated for four to 10 days. The plants act like mini-bioreactors, producing the [virus-like particles] in their leaves.”

Optimizing Vitamin D Effective During Flu Season

One can only speculate, at this point, what the side effects of injecting a genetically engineered tobacco plant-based flu vaccine into your body might be. Fortunately, you don’t have to pin your hopes on such developments — studies have repeatedly demonstrated the excellent track record of vitamin D for preventing respiratory infections. Most recently, a 2017 scientific review18,19 of 25 randomized controlled trials found that vitamin D supplementation cuts rates of acute respiratory infections among all participants.

The studies included nearly 11,000 individuals from more than a dozen countries, and showed that people who regularly took vitamin D supplements were less likely to contract acute respiratory tract infections compared to those who did not take supplemental vitamin D. Those with blood levels below 10 ng/mL, which is a serious deficiency state, cut their risk of infection by half.

People with higher vitamin D levels reduced their risk by about 10 percent. According to this international research team, vitamin D supplementation could prevent more than 3.25 million cases of cold and flu each year in the U.K. alone.20 Another statistic showing vitamin D is a very effective strategy in preventing respiratory illness during the flu season is the NNT.

As mentioned at the beginning of this article, the Cochrane Collaboration concluded in 2014 that the NNT for the flu vaccine is 71. In this 2017 respiratory infection study, the NNT for vitamin D was 33, meaning one person would be spared from acute respiratory infection for every 33 people taking a vitamin D supplement.

Among those with severe vitamin D deficiency at baseline, the NNT was 4. If you’re going to gamble, which odds would you rather have — a 1 in 71 chance of being protected against respiratory infection, or a 1 in 33 chance (or 1 in 4 should you be severely vitamin D deficient)? In my view, optimizing your vitamin D levels is one of the absolute best respiratory illness prevention and optimal health strategies available.

Tamiflu or Quercetin?

Should you or your child get sick and a doctor or pediatrician recommends Tamiflu,21 please understand that this antiviral drug shortens the duration of flu symptoms by less than 17 hours.22,23 It also does not reduce viral transmission and does not lower your risk of complications, such as pneumonia.24,25

Some scientists have also warned that Tamiflu’s serious risks outweigh the benefits.26 These risks include convulsions, brain infections, psychosis and other neuropsychiatric problems.27,28 The drug is particularly risky for children, and more than half of all children taking Tamiflu suffer side effects from the drug.29,30

Considering Tamiflu’s risks and limited effectiveness, quercetin is safe and effective. Quercetin, a plant flavonol found naturally in apples, plums, red grapes, green tea, elder flower and onions, packs a powerful antiviral punch.31 Some of its mechanisms of action include inhibiting the ability of viruses to infect cells and inhibiting replication of already infected cells. A number of studies have confirmed quercetin’s effectiveness against viral infections, including the following:

A 2010 animal study found that quercetin inhibits both influenza A and B viruses. Two other important discoveries were made. Firstly, the viruses were unable to develop resistance to quercetin and, secondly, when used concomitant with antiviral drugs (amantadine or oseltamivir), the effect was significantly amplified — and it prevented drug-resistance from developing.33

A 2004 animal study investigating quercetin’s effect on influenza used a strain of the H3N2 virus. According to the authors:34

“In the mice, instillation of influenza virus A/Udorn/317/72(H3N2) intranasally resulted in a significant decrease in the pulmonary concentrations of catalase, reduced glutathione and superoxide dismutase … These effects were observed on the 5th day after viral instillation.

Oral supplementation with quercetin simultaneous with viral instillation produced significant increases in the pulmonary concentrations of catalase, reduced glutathione and superoxide dismutase …

It is concluded that during influenza virus infection, there is ‘oxidative stress.’ Because quercetin restored the concentrations of many antioxidants, it is proposed that it may be useful as a drug in protecting the lung from the deleterious effects of oxygen derived free radicals released during influenza virus infection.”

In 2014, researchers noted that quercetin appears to be “a promising treatment for the common cold,” caused by the rhinovirus, adding that “Quercetin has been shown to reduce viral internalization and replication in vitro, and viral load, lung inflammation and airways hyper-responsiveness in vivo.”35

By attenuating oxidative damage, it also lowers your risk of secondary bacterial infections, which is actually the primary cause of influenza-related deaths. Importantly, quercetin increases mitochondrial biogenesis in skeletal muscle, which suggests part of its antiviral effects are due to enhanced mitochondrial antiviral signaling.

A 2016 study found quercetin offered protection against influenza A virus H1N1 by modulating protein expression. More specifically, the regulation of heat shock proteins, fibronectin 1 and prohibitin was instrumental in reducing viral replication.36

A second study published in 2016 found quercetin inhibited a wide spectrum of influenza strains, including H1N1, H3N2 and H5N1. According to the authors, “This study indicates that quercetin showing inhibitory activity in the early stage of influenza infection provides a future therapeutic option to develop effective, safe and affordable natural products for the treatment and prophylaxis of [influenza A viruses] infections.”37

Prevention of Respiratory Infections Shouldn’t Be so Risky

Aside from vitamin D and quercetin, maintaining good levels of vitamins B1 and C may go a long way toward keeping you healthy through the flu season and beyond. Influenza has also been treated with high-dose vitamin C,38 and vitamin C also boosts the effectiveness of quercetin. Taking zinc lozenges at the first sign of respiratory illness can also be helpful.